[Venezuelan consensus guidelines on the use of magnetic resonance in diagnosis and follow up of patients with multiple sclerosis]

INTRODUCTION

The clinical use of magnetic resonance (MR) in patients with multiple sclerosis (MS) has advanced markedly over the past few years. Several groups around the world have developed consensus guidelines about the role of MR in MS at diagnosis and during follow up. However, in some regions is difficult to extrapolate the recommendations.

AIM

To provide recommendations for the implementation of MR in MS patients at diagnosis and follow up in Venezuela.

DEVELOPMENT

A group of experts from Venezuela that included neurologists and radiologists, by using the online surveys methodology as well as face to face meetings developed the intended consensus for the use of MR during the diagnosis and follow up of MS patients in Venezuela. Seventeen recommendations were established based on published evidence and the expert opinion. Recommendations focused on the role of conventional MR techniques and brain atrophy measurement in MS patients both at diagnosis and during follow-up.

CONCLUSIONS

The recommendations of this consensus guidelines attempts to optimize the health care and management of patients with MS in Venezuela.

Noninvasive measurement of dissipation in colloidal systems

According to Harada and Sasa [Phys. Rev. Lett. 95, 130602 (2005)], heat production generated in a nonequilibrium steady state can be inferred from measuring response and correlation functions. In many colloidal systems, however, it is a nontrivial task to determine response functions, whereas details about spatial steady state trajectories are easily accessible. Using a simple conditional averaging procedure, we show how this fact can be exploited to reliably evaluate average heat production. We test this method using Brownian dynamics simulations, and apply it to experimental data of an interacting driven colloidal system.

Role of hidden slow degrees of freedom in the fluctuation theorem

The validity of the fluctuation theorem for entropy production as deduced from the observation of trajectories implicitly requires that all slow degrees of freedom are accessible. We experimentally investigate the role of hidden slow degrees of freedom in a system of two magnetically coupled driven colloidal particles. The apparent entropy production based on the observation of just one particle obeys a fluctuation theorem-like symmetry with a slope of 1 in the short time limit. For longer times, we find a constant slope, but different from 1. We present theoretical arguments for a generic linear behavior both for small and large apparent entropy production but not necessarily throughout. By fine-tuning experimental parameters, such an intermediate nonlinear behavior can indeed be recovered in our system as well.

[Complications of laparoscopic cholecystectomy]

The laparoscopy cholecistectomy is a surgical procedure described in 1987, and it has had an important apogee and it's had substitute to open procedure. Between its advantages is notable, the postoperatory evolution without pain, paralytic ileus and the short time of hospitalization besides the patient can go away the same day in some cases. In Venezuela, the procedure has been received with enthusiasm by the surgeons with prefer this procedure however, there are complications derived in part for the lack of experience in the first cases, but occur non related of the experience. The quantization of the complications is not simple to realize for different reasons. We present twelve complications, two belong to patients intervened in the Hospital Universitario de Caracas and ten belong to patient transferred from other center. The complications were: pseudoaneurism of hepatic artery, hematoma of the wall, cutting of common bile duct, section the right bile duct, abscess of vesicular bed in two cases, retropneumoperitoneum, ascites by biliary fistula and four biloma. The treatment varied in every case and the utilization of radiologic technique with percutaneous drainage were useful in five cases. We conclude: first, this technique is not free of complications. Second, the percutaneous drainage (abscess, biloma), endoscopic procedure (biliary prosthesis) in fistulaes and arteriographics (arterial embolization), are useful in some cases, and could prevent the surgical reintervention.

[Potassium-dependent modification of the lidocaine effect: an experimental investigation (author's transl)]

Lidocaine was supplied to 10 cats by 2 comparative infusions of 7.5 mg/kg respectively. Once the drug was dissolved in a physiological and the other time in a K-Mg-concentrated electrolyte solution. The sequence of both infusions alternated. Serum potassium remained constant during infusion of the physiological electrolyte solution, but increased by about 1 mEqu/1 under K-concentrated solution. Lidocaine caused an enhancement of ventricular fibrillation threshold to an absolutely identical degree in both groups. Increase in cardiac output and stroke volume and decrease of sinus rate was significant in both groups, but more pronounced under K-Mg concentrated solution. Mean arterial pressure, peripheral vascular resistance, PQ, QRS, and QT interval remained constant on the whole. We deduce from these results for antiarrhythmic therapy on normokalemic patients, that the addition of potassium and magnesium to lidocaine solution does not enhance its antifibrillatory effect. This statement is valid for doses up to 20 mEqu/h of magnesium and 40 mEqu/h of potassium.